Sliding Window Protocols with Rate Adaptation for FSO Burst Transmission over Turbulence Channels

This paper addresses the cross-layer design of error-control protocols with rate adaptation for free-space optical (FSO) burst transmission over atmospheric turbulence channels. In particular, sliding window automatic repeat request (ARQ) protocols are designed so that the window size is determined by the burst duration. This facilitates an effective operation of sliding window protocols with the adaptive rate (AR) transmission over the strong atmospheric turbulence channels. To analyze the performance of the design, the time-varying behavior of the atmospheric turbulence channels, modeled the popular Gamma-Gamma (ΓΓ) distribution, is captured by a finite Markov chain. The channel model is then used to develop the burst error model for the cross-layer performance analysis of sliding window protocol with AR transmission. Numerical results quantitatively demonstrate the impact of atmospheric turbulence on the system performance, and support the optimal selection of system parameters over turbulence conditions. Monte Carlo simulations are also performed to validate the analytical results.